Basement membranes are complex, extracellular matrices that play a role in vital functions, such as embryogenesis, tissue organization, vascular architecture and kidney glomerular filtration. The major components of basement membranes that have been identified include Type IV collagen (P. Bornstein et al., Annu. Rev. Biochem. 49:957 (1980), and N. A. Kefalides, Biology and Chemistry of Basement Membranes (1978), Academic Press, New York); fibronectin (E. Ruoslahti et al., Coll. Res. 1:95 (1981)); the glycoprotein CP-1 (A. E. Chung et al., Biochem. Biophys. Res. Commun. 79:879 (1977)); the glycoprotein CP-2 (A. E. Chung et al., Cell 16:277 (1979)); laminin (J. M. Foidart et al., Lab. Invest. 42:336 (1980)); heparan sulfate, (Y. S. Kanwar et al., Proc. Natl. Acad. Sci. U.S.A. 76:1303,76:4493 (1979); and entactin (B. Carlin et al., J. Biol. Chem. 256:5209 (1981) and B. L. Bender et al., Am. J. Pathol. 103:419 (1981). It would appear that the glycoproteins GP-1 and GP-2 form the laminin complex. (R. Timpl et al., J. Biol. Chem. 254:9933 (1979)).
Basement membranes are found at the base of epithelial and endothelial cells and at the interface between cells and the connective tissue matrices. They are synthesized by a variety of cells including the endothelium of the capillaries, the epithelium of the kidney glomerulus and tubule, the parietal endoderm of the yolk sac, the epithelial cells of lens capsule, and the epithelium of glandular, respiratory and gastrointestinal tissues. The membranes undergo morphological and presumably functional changes under a variety of pathological states such as systemic lupus erythematosus, diabetes mellitus, Goodpasture's syndrome, and post-streptococcal glomerulonephritis (N. A. Kefalides, J. Invest. Dermatol. 65:85 (1975)). In these diseases, different tissues are affected e.g. in diabetes mellitus the basement membranes of both the kidney glomerulus and the capillaries of muscle are affected. The variety of functions of basement membranes suggest the possibility of microheterogeneity of the macromolecular components and diversity in their organization. Among the functions which have been ascribed to basement membranes are (a) filtration, notably of plasma in the kidney glomeruli, (b) organization of tissues and organs by delineation of boundaries between groups of cells and (c) provision of a matrix for cell adhesion. (M. G. Farquhar, Biology and Chemistry of Basement Membranes (1978), pp. 43-80, Academic Press, New York).
The precise roles of these macromolecules within the basement membrane are not understood in detail at present. Fibronectin has been shown to have effects on cell morphology (L. B. Chen et al., Cell 14:377 (1978)), adhesion (I. U. Ali et al., Cell 11:115 (1977)) and contact inhibition (K. M. Yamada et al., Proc. Nat'l Acad. Sci. U.S. 73:1217 (1976)). Heparan sulfate has been suggested to play a key role in glomerular filtration by virtue of its negative charge (Y. S. Kanwar et al., Proc. Nat'l. Acad. Sci. U.S. 76:1303 (1979)). It is believed that the sulfated glycoprotein entactin may play a similar role. Several lines of evidence also indicate that glycoprotein GP-2 (A. E. Chung et al., Cell 16:277 (1979)), entactin (B. Carlin et al., J. Biol. Chem. 256:5209 (1981) and B. L. Bender et al., Amer. J. Pathol. 103:419 (1981)) and laminin are involved in cell adhesion and early embryogenesis in the mouse (P. Ekblom et al., Proc. Nat'l. Acad. Sci. U.S. 77:485 (1980)).
There still exist voids in the understanding of the structure and biosynthesis of basement membranes. In an effort to better understand the structure and biosynthesis of basement membranes and its components, and to better correlate structural organization with function, hybridoma cell lines have been developed that produce monoclonal antibodies directed against the basement membrane components.
Although hybridoma cell lines that produce monoclonal antibodies, such as antibodies to hepatitis virus, are known in the prior art, e.g. the cell lines disclosed in U.S. Pat. No. 4,271,145, hydriboma cell lines that produce monoclonal antibodies against laminin are unknown.
A hydridoma cell line has now been developed that provides an unlimited supply of a unique and unchanging antibody that is directed against the basement membrane component laminin, or more specifically the glycoprotein GP-2, a subunit of the laminin complex. This novel cell line and the resulting antibody can be used for medical diagnoses, studies on development of animal embryos and a variety of research activities involving the structure and function of basement membranes.